In order to improve the efficiency of computer identification, enhance its flexibility and accuracy, and enable people to get rid of the complicated statistical identification work, traditional barcode, two-dimensional barcode, and radio frequency identification technologies have emerged. Although they have their own advantages, no matter which technology is used, it is to obtain various information of items in time and process them quickly and accurately.

The technology of traditional barcode (also called one-dimensional barcode) is relatively mature, which can be seen everywhere in social life and has been widely used all over the world. As a means of computer data collection, it quickly enters various fields such as commodity circulation, automatic control, and file management with many advantages such as fast, accurate, low cost, etc. It is also the most used barcode in China at present. However, because the traditional barcode is one-dimensional, it does not carry any information in the vertical direction, has low information density, and cannot display Chinese characters. It is easy to be refused to read because of wear or wrinkles, which largely limits the application scope of the traditional barcode.

1、 Narrow one-dimensional space

The traditional barcode is composed of a group of bar and space symbols arranged according to certain coding rules, representing certain characters, numbers and symbol information. Bar code system is an automatic identification system composed of bar code symbol design, bar code production and scanning reading. It is the most widely used automatic identification technology so far.

So far, there are more than 20 common barcode coding systems, including EAN code, Code39 code, cross 25 code, UPC code, 128 code, Code93 code, and CODABAR code. Different coding systems have different characteristics and are applicable to specific application fields. Here are some typical coding systems:

1. UPC code (unified commodity barcode)

The UPC code was introduced by the American Supermarket Union in 1973. It is the first commercial barcode system in the world, mainly used in the United States and Canada. UPC codes include UPC-A and UPC-E systems. UPC only provides digital codes, limits the number of digits (12 digits and 7 digits), requires check codes, allows two-way scanning, and is mainly used in supermarkets and department stores.

2. EAN code (European commodity barcode)

In 1977, 12 European industrial countries signed a draft agreement in Belgium, established the International Bar Code Association for Commodities, and formulated compatible EAN codes with reference to UPC codes. The EAN code has only a digital number, usually 13 digits, which allows two-way scanning and shortens the code to 8 digits. It is also mainly used in supermarkets and department stores.

3. ITF25 code (cross 25 code)

The barcode length of ITF25 code is not limited, but its digital data must be even digits, allowing two-way scanning. ITF25 code is widely used in logistics management, mainly for packaging, transportation, ticket serial number of international aviation system, automobile industry and retail industry.

4. Code39

Among the 9 code elements of Code 39, 3 code elements must be thick lines, so Code 39 is also called "39 Code". In addition to the numbers 0-9, Code39 also provides the English letters A-Z and special symbols. It allows two-way scanning and supports 44 groups of barcodes. It is mainly used in industrial products, commercial materials, libraries and other places.

5. CODABAR code (Kudebar code)

This code system can support numbers, special symbols and four English letters. Since the barcode has the detection function, it is unnecessary to check the code. It is mainly used in factory inventory management, blood bank management, library borrowing books and photo development industry.

6. ISBN code (international standard book number)

ISBN is a set of international uniform coding system for the needs of book publishing and management, as well as facilitating the exchange and statistics of international publications. Each ISBN code is composed of a group of ten digits with "ISBN" code, which is used to identify the country, region, publishing institution, title, version and binding method of the publication. This group of numbers can also be said to be representative numbers of books, most of which are used in the book management system of publishing houses.

7. Code128

Code128 is a code system customized by Chinese enterprises. The length and information of the barcode can be determined according to needs. The information contained in this code can be numbers or letters, and is mainly used in industrial production lines, book management, etc.

8. Code93

This code system is similar to Code39, but its density is higher and can replace Code39.

The great changes that barcode technology brings to people's work and life are obvious to all. However, because the information capacity of one-dimensional barcode is relatively small, for example, the barcode on the commodity can only contain a few or dozens of Arabic numerals or letters, so one-dimensional barcode can only identify a type of commodity, and does not include descriptions of related commodities. Only with the help of the database, people can get the description of relevant goods through barcode. In other words, if you leave the pre established database, the information contained in one-dimensional barcode will be greatly reduced. For this reason, the use of one-dimensional barcode is quite limited in places where there is no database support or networking is inconvenient.

On the other hand, one-dimensional barcode cannot represent Chinese characters or image information. Therefore, in some occasions where Chinese characters and images need to be used, one-dimensional barcode is very inconvenient. Moreover, even if we have established a corresponding database to store Chinese characters and image information of related products, these large amounts of information also need a long barcode for identification. This kind of long bar code will occupy a large printing area, which brings difficulties to printing and packaging. Therefore, people want to directly include various product related information in the barcode, and do not need to query these information from the database again according to the barcode.

Based on the above reasons, the practical application needs a new coding system, which should not only have the advantages of one-dimensional barcode, but also have the advantages of large information capacity, high reliability, strong confidentiality and anti-counterfeiting.

In the 1970s, two-dimensional barcode technology appeared in the field of computer automatic identification, which is a coding technology developed on the basis of traditional barcode. It expands the information space of barcode from linear one-dimensional to planar two-dimensional, and has many advantages such as large information capacity, low cost, high accuracy, flexible coding mode, strong confidentiality, etc. Therefore, since 1990, two-dimensional barcode technology has been widely used in the world. After several years of efforts, it has been applied in national defense, public security, transportation, medical care, industry, commerce, finance, customs and government management.

2、 A leap from "line" to "face"

2D barcode vs traditional barcode

Unlike one-dimensional barcode, which can only read data from one direction, two-dimensional barcode can obtain information from both horizontal and vertical directions. Therefore, it contains much more information than one-dimensional barcode, and also has the function of self correction. However, the working principle of two-dimensional barcode is similar to that of one-dimensional barcode. When identifying, two-dimensional barcode is printed on paper tape. Reading the information contained in barcode symbols requires a scanning device and a decoding device, which are collectively called readers. The function of the reader is to convert the bar code bar width, spacing and other spatial signals into different output signals, and then convert the signals into binary codes that can be recognized by the computer and input them into the computer. The scanner, also known as photoelectric reader, is equipped with a light source to illuminate the read barcode and a photoelectric detector, and can receive the reflected light of the barcode. When the light from the scanner shines on the paper tape, each photocell outputs different patterns according to the presence or absence of the barcode on the paper tape. The patterns from each photocell are combined to generate a high-density information pattern, which is amplified and quantized and then sent to the decoder for processing. The decoder stores the barcode coding scheme database and decoding algorithm to be translated. In the early recognition equipment, scanner and decoder were separated, and most of the current equipment has been integrated.

The two-dimensional barcode has the following characteristics:

Large storage capacity. The two-dimensional barcode can store 1100 characters. Compared with the 15 characters of the one-dimensional barcode, the storage capacity is greatly increased, and it can store Chinese. Its data can not only be used in English, numbers, Chinese characters, marks, etc., but also can be processed even blank. The size can be freely selected, which is also impossible for the one-dimensional barcode.

High resistance to damage. The two-dimensional barcode adopts fault correction technology, which can be recovered even if it is polluted or damaged. Even if the barcode is damaged by up to 50%, the original data can still be interpreted, with a misreading rate of 61 million.

High security. The encryption technology is adopted in the two-dimensional barcode, so the security is greatly improved.

It can be faxed and photocopied. The two-dimensional barcode can still be used after faxing and photocopying, while the one-dimensional barcode cannot be read by the machine after faxing and photocopying.

Print diversity. As for two-dimensional barcode, it can not only print black words on white paper, but also color printing, and the printing machine and printing objects are not limited, which is very convenient for printing.

Strong anti-interference ability. Compared with magnetic card and IC card, two-dimensional barcode has strong antimagnetic and anti-static capabilities due to its own characteristics.

More codes

The two-dimensional barcode can be directly printed on the scanned article or printed on the label, and the label can be specially printed or printed on site by the supplier. All barcodes have some similar components. They all have a blank area, called the quiet area, which is located outside the edge of the start and end of the barcode. The check symbol is also necessary in some code systems. It can check the barcode with mathematical methods to ensure that the decoded information is correct. Like one-dimensional barcode, two-dimensional barcode has many different encoding methods. According to these coding principles, two-dimensional barcodes can be divided into the following three types:

One is linear stacked QR code. That is, on the basis of one-dimensional barcode, reduce the height of the barcode line, arrange a long and narrow bar code line with a large aspect ratio, and stack each line on the top. Each line is separated by a thick black bar with a module width. Typical linear stacked QR codes include Code 16K, Code 49, PDF417, etc.

The second is the matrix QR code. It uses a unified combination of black and white squares, rather than a combination of bars and spaces of different widths. It can provide higher information density and store more information. At the same time, the matrix barcode has higher automatic error correction capability than the stack barcode, and is more suitable for situations where the bar code is vulnerable to damage. Matrix symbols do not identify the starting and ending modules, but they have some special "locators", which contain information such as the size and orientation of the symbol. Matrix two-dimensional barcode and new stacked two-dimensional barcode can recover data from damaged barcode symbols with advanced mathematical algorithms. Typical matrix QR codes include Aztec, Maxi Code, QR Code, Data Matrix, etc.

The third is postal code. It is encoded by bars of different lengths, mainly used for mail encoding, such as Postnet, BPO 4-State, etc.

In the two-dimensional barcode introduced above, the PDF417 code is widely used due to its open and commercialized decoding rules. It is the abbreviation of Portable Data File, which means that the barcode can be regarded as a file, which can store more information and can be carried around. It was officially launched in 1992. In 1995, the Bar Code Committee of the Electronic Industry Association of the United States completed the draft of two-dimensional bar code standard under the sponsorship of the National Standards Association of the United States to serve as the standard for the use of two-dimensional bar codes in the production and marketing process of electronic products. The PDF417 code is a multi line structure. Each line of data has the same number of symbols. The lines are aligned to the left and right directly. The minimum number of lines is 3 and the maximum number of lines is 90. The Data Matrix code is mainly used for the identification of small parts in the electronic industry. For example, this code is printed on the back of the Intel Pentium processor. Maxi Code is developed by United Parcel Service in the United States for parcel sorting and tracking. Aztec is introduced by Welling Company in the United States, which can hold data of 3832 numbers, 3067 letters or 1914 bytes at most.

In addition, there are some new two-dimensional barcode systems. Including the UPS Code developed by Figuere lla and others of UPS, which is suitable for motion characteristics in distributed environments. This two-dimensional barcode is more suitable for automatic classification applications. Veritec, an American company, has proposed a new two-dimensional barcode, Veritec Symbol, which is a binary data encoding system for micro and small products. Its matrix symbol format and image processing system have been patented in the United States. This two-dimensional code has higher accuracy and repeatability. In addition, WILJ WAN GILS et al. of Philips Research Laboratory also proposed a new two-dimensional code scheme, that is, the dot matrix two-dimensional code representation of product identification mark on automatic production line is formed by using standard geometric shape dots. This scheme consists of two parts: one is the source coding system, which is used to convert the coding of identification marks into communication information words; The other part is channel coding system, which is used for error detection and correction of random error codes. There is also a two-dimensional bar code called dot matrix code. In addition to its high information density, it is also convenient to print dot codes on mechanical parts by engraving and etching board making process, read them by camera equipment and identify them by image processing system, which is also a two-dimensional coding scheme with great application potential.

The development of two-dimensional bar code technology is mainly manifested in three aspects: first, a more information intensive coding scheme has emerged, which enhances the function of bar code technology information input; Secondly, the development of small, micro, high-quality hardware and software makes barcode technology more practical and expands the application field; The third is mutual penetration and promotion with other technologies, which will change the structure and performance of traditional products and expand the functions of the barcode system.

Reader of two-dimensional barcode

There are several important parameters in the two-dimensional barcode reader: resolution, scanning background, scanning width, scanning speed, one-time recognition rate, bit error rate, which should be selected according to different applications. Common barcode readers usually use the following three technologies: light pen, CCD and laser. They all have their own advantages and disadvantages. No reader can have advantages in all aspects.

The light pen is the first handheld contact barcode reader. When using, the operator needs to touch the light pen to the barcode surface and send a small light dot through the lens of the light pen. When the light dot crosses the barcode from left to right, the light is reflected in the "empty" part and the light is absorbed in the "bar" part. Therefore, a variable voltage is generated inside the light pen, which is used for decoding after amplification and shaping.

CCD is an electronic coupling device, which is more suitable for close distance and contact reading. It uses one or more LEDs, and the light emitted can cover the entire barcode. It focuses not on each "bar" or "empty", but on the whole barcode, and converts it into an electrical signal that can be decoded.

The laser scanner is non-contact, and the laser reader is the only choice when the reading distance exceeds 30cm. Its first reading recognition success rate is high, the recognition speed is faster than that of light pen and CCD, and the recognition effect is good for the bar code with poor printing quality or fuzzy.

RFID technology has changed the way in which barcode technology relies on "tangible" one-dimensional or two-dimensional geometric patterns to provide information, and chips are used to provide a larger number of "intangible" information stored therein. It first appeared in the 1980s, and was initially applied in some special industrial occasions where barcode tracking technology could not be used. For example, in some industries and companies, this technology was used for target positioning, identification and tracking inventory products. RFID technology started relatively late, and no unified international standard has been formulated so far. However, the introduction of RFID technology is not only an improvement of information capacity, but also a revolution for computer automatic identification technology. Its powerful advantages will greatly improve the efficiency and accuracy of information processing.

3、 Revolution from "visible" to "invisible"

Huge advantages

Compared with barcode identification system, radio frequency identification technology has many advantages: it can automatically identify the target object through radio frequency signal without visible light source; With penetrability, data can be directly read through external materials to protect external packaging and save unpacking time; RF products can work in harsh environments with low environmental requirements; The reading distance is far, and the data can be obtained without contacting the target; Support data writing, without the need to re create new labels; The anti-collision technology can handle multiple RF tags at the same time, which is suitable for batch identification; It can track and locate objects attached to RFID tags to provide location information.

Due to the advantages of RFID products, RFID technology has developed rapidly abroad. It has been widely used in industrial automation, commercial automation, transportation control management and many other fields, such as traffic monitoring systems for cars or trains, automatic toll collection systems for highways, goods management, automation of assembly line production, access control systems, financial transactions, storage management, livestock management, vehicle theft prevention, etc. In Australia, RFID technology has been used in the management of airport passenger baggage, which has improved the working efficiency of the airport and achieved ideal benefits; On the other side of the earth, the European Community announced that the new cars produced in 1997 must have anti-theft systems based on RFID technology; The Swiss National Railway Administration will also install RFID automatic identification systems on all passenger trains in Switzerland, so that dispatchers can master the train operation in real time, which is not only conducive to management, but also greatly reduces the possibility of accidents; Lufthansa is trying to replace air tickets with RFID tags, thus changing the traditional way of ticket purchase and sales. Up to now, new applications of RFID technology are still emerging one after another.

Due to the miniaturization of RFID chips and the practicality of high-performance chips, RFID tags not only help managers in different fields track the location and handling of items, but also can report other information attached to tags in real time, such as temperature and pressure. RF tags provide such information through readers connected to the data network. Up to now, RFID tags have been mainly used in factory automation or inventory management as an extension of barcode, but ultimately, smaller RFID tags will be used in more advanced fields. For example, RFID tags can promote the application of network appliances. If appliances have network functions, users can control them even outdoors. For example, they can check the food in the refrigerator, help users decide what items to buy, and choose the way to cook food on the wireless operating terminal. At present, manufacturers of electrical equipment and household appliances have begun to develop general software and hardware, and are considering formulating application standards for RFID tags on various household appliances. Applying RFID tags to hospitals can also bring benefits. As soon as a patient enters a hospital, he or she will wear a tag. The tag contains the patient's identification information. Doctors and nurses can identify the patient's identity through the data in the tag to avoid misidentification of the patient. Tags and readers can also help doctors and nurses confirm whether the drugs used are appropriate, so as to avoid medical accidents.

RFID starts to enter the practical stage

According to statistics, at present, about 5000 RFID systems have been installed around the world, and the actual annual sales volume is about 964 million dollars, but they are mainly used in limited fields such as pet and wildlife tracking, highway and parking fees. In fact, RFID is expected to play a significant role in many fields. Now, many enterprises have applied it to some new fields tentatively.

Gillette is the world's largest manufacturer of razors. Because of its small size and high unit price, its products are often "favored" by thieves. To this end, Gillette has decided to use RFID technology to prevent product theft. It has established a project executive committee composed of senior managers and an RFID project office, which are respectively responsible for guiding and coordinating the daily management of the project, and has included relevant responsibilities in the performance appraisal of employee target management. Gillette divided the project into two stages, and implemented it from two aspects: internal operation and shelf management of retailers: first, Gillette selected "Sharp Speed 3" to conduct shelf tests in a few places, and then it will be promoted to all eight product lines after success; In the second stage, Gillette plans to integrate it into the entire supply chain, realizing seamless tracking and management of the whole process of products from the factory to the retailer's distribution center, to the shelves and to the hands of the final consumers.

At present, Gillette has completed the first phase of experiments with Wal Mart and Tesco in Boston, USA and Cambridge, UK respectively: Gillette implanted RFID tags into the packaging of "Spice3", and installed readers on the retailers' shelves. If a customer takes multiple razors at one time, the system will remind the clerk to check whether theft has occurred, or even automatically take photos, When the inventory on the shelf is reduced to a certain level, the system will send a replenishment signal, and the test results are very satisfactory. It is said that the second phase of the test will be officially launched soon. It is worth mentioning that Gillette has ordered a total of 500 million RFID tags from Allen Technologies, one of the RFID tag manufacturers. This is undoubtedly a significant milestone in the large-scale substantive commercialization of low-cost RFID tags.

Metro Group, an international famous retail enterprise, has recently adopted the RFID solution of Philips Semiconductor in its business operation. This technology can help it improve the supply chain efficiency in retail and improve the shopping experience of consumers. This RFID technology can identify products in real time, guard against theft, track inventory, and view the status of customers' credit cards. The system operates at 13.56MHz, with an effective recognition range of 1.5m. It is connected to the RFID multimedia studio. Consumers can see an introductory preview of the album or movie they are buying by scanning a CD or DVD. Cosmetics and food are also labeled and placed on smart shelves. This application can provide real-time inventory and shelf life control, timely update sales data, and discover misplaced items.

Recently, Wal Mart also said that it would no longer purchase goods from suppliers that did not use RFID technology in the future, which shocked the application software industry greatly. Now, Sun is developing a corresponding middleware product to manage the commodity data obtained from the RFID system. The product is now in the testing stage and is expected to be launched for commercial use this year. In addition, Sun is also developing information service software that conforms to the RFID industry standard EPC.

Once the chips and tags used for RFID are introduced, corresponding special software is needed to manage these data. Fortunately, many large software developers and system integrators have begun to enter the RFID field. SAP, Manhattan Associates, IBM and other companies will launch their own solutions. SAP said publicly that it and P&G were conducting a series of technical innovation and cooperation to integrate RFID data into SAP/R3 system. The system is called AutoID, which can protect the system from acquiring only valuable data and avoiding the interference of incorrect data. In addition, IBM also demonstrated its RFID system in the Electronic Code Symposium. The company can provide a complete solution for RFID. It can realize a full set of business processes from manufacturers, distributors, and retailers without having to cross systems. However, integration remains challenging. According to the developer, the price is quite expensive, and it is still challenging to launch a complete RFID software system before the deadline of January 2006.

In addition, labels will also be a huge market, especially at a high price of 20 cents to 30 cents. Because the buyer is in the leading position in the market, Wal Mart may require that the price of RFID labels be reduced to an acceptable level, but it is unknown whether the supplier can provide the corresponding technology.